logger

Logger

The logger package implements the core logging functionality.

You can set your logger which implements the Logger interface or use the standard logger.

By default, the standard logger is initialized:

• with the time format 2006/01/02 15:04:05.000;
• with logging format FormatText;
• at the highest logging level LevelTrace;
• printing the name of the calling function false.

You can set the required time format, level, log message format and additional output, as in the following examples:

• at initialization

package main

import (
	"os"

	"github.com/gromey/proto-rest/logger"
)

func main() {
	file, err := os.OpenFile("logs.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		panic(err)
	}

	defer func() {
		if err = file.Close(); err != nil {
			panic(err)
		}
	}()

	logger.Info("Hello World!")
	// 2006/01/02 15:04:05.000 INFO [1] /../../main.go:21 Func: main() Hello World!

	lCfg := new(logger.Config)
	lCfg.TimeFormat = "2006-01-02 15:04:05"
	lCfg.Format = logger.FormatJSON
	lCfg.AdditionalOut = file
	lCfg.Level = logger.LevelInfo
	lCfg.FuncName = true

	logger.SetLogger(logger.New(lCfg))

	logger.Info("Hello World!")
	// {"time":"2006-01-02 15:04:05","level":"INFO","thread":1,"func":"main()","message":"Hello World!"}
}

• after initialization

package main

import (
	"os"

	"github.com/gromey/proto-rest/logger"
)

func main() {
	l := logger.New(nil)
	logger.SetLogger(l)

	file, err := os.OpenFile("logs.log", os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
	if err != nil {
		panic(err)
	}

	defer func() {
		if err = file.Close(); err != nil {
			panic(err)
		}
	}()

	l.SetTimeFormat("2006-01-02 15:04:05")
	l.SetFormatter(logger.FormatJSON)
	l.SetAdditionalOut(file)
	l.SetLevel(logger.LevelInfo)
	l.SetFuncNamePrinting(false)

	logger.Info("Hello World!")
	// {"time":"2006-01-02 15:04:05","level":"INFO","thread":1,"message":"Hello World!"}
}

To reduce unnecessary memory allocations, it is recommended to check the logging level before calling the log function.

Example:

	if logger.InLevel(logger.LevelInfo) {
		logger.Info("Hello World!")
	}